Tumors Of The Skin PDF

TUMORS OF THE SKIN Benign Lesions-Seborrheic keratosis Common pigmented epidermal tumor middle-age or older individuals arise spontaneously trunk, extremities, head, and neck Benign Lesions-Seborrheic keratosis activating mutations in growth factor signaling pathways activating mutations in fibrob...

TUMORS OF THE SKIN Benign Lesions-Seborrheic keratosis Common pigmented epidermal tumor middle-age or older individuals arise spontaneously trunk, extremities, head, and neck Benign Lesions-Seborrheic keratosis activating mutations in growth factor signaling pathways activating mutations in fibroblast growth factor receptor 3 (FGFR3), RAS and PI3K Benign Lesions-Seborrheic keratosis Except for cosmetic concerns, seborrheic keratoses are usually of little clinical importance. Leser-Trelat: hundreds of lesions may appear suddenly as a paraneoplastic syndrome. internal malignancies, most commonly gastrointestinal tract carcinomas, which produce growth factors that stimulate epidermal proliferation. Benign Lesions-Seborrheic keratosis Morphology: Seborrheic keratoses are round, exophytic, coinlike plaques that vary in diameter from millimeters to centimeters and have a “stuck-on” appearance. They are tan to dark brown and have a velvety- to granular-appearing surface. Occasionally, their dark color is suggestive of melanoma, leading to surgical removal. Benign Lesions-Seborrheic keratosis monotonous sheets of small cells that resembling basal cells of the normal epidermis. Variable melanin pigmentation is present within these basaloid cells Hyperkeratosis small keratin-filled cysts (horn cysts) downgrowth of keratin into the main tumor mass (pseudo–horn cysts) Benign Lesions-Seborrheic keratosis Benign Lesions-Fibroepithelial Polip Acrocordon, skin tag Middle aged neck, trunk, face may be associated with Birt-Hogg-Dubé syndrome Benign Lesions-Fibroepithelial Polip Polypoid Fibrovascular core Covered with epidermis  Benign Lesions-Epithelial/Follicular Cysts Young and middle aged adults Face, neck, trunk smooth dome shaped swellings varying in size from a few millimeters to a few centimeters mobile unless ruptured, in which case a foreign body giant cell reaction may make them more adherent to surrounding connective tissue Benign Lesions-Epithelial/Follicular Cysts Epidermis or follicles invaginate through dermis and become cystic Cyst contents white, cheesy macerated keratin that may have an odor Benign Lesions-Melanocytic nevi Junctional nevus: small, flat or slightly elevated Rounded nests of melanocytes / nevus cells on epidermal side of dermoepidermal junction, originating from tips of rete ridges Premalignant lesions-Actinic Keratosis result of chronic exposure to sunlight, UV-induced DNA damage The rate of progression to SCC 0.1% to 2.6% per year Most regress or remain stable usually